Auburn deputy mayor Salim Mehajer has denied allegations that he threatened the family of a Sydney siege survivor Joel Herat after an altercation with Mr Herat's father at a Burwood gym, saying he planned to sue the company for damages, Channel Nine has reported.

Bruce Herat, who works at the Anytime Fitness gym on Railway Parade as a personal trainer, was allegedly confronted by Mr Mehajer after he requested he stop dropping weights on the gym's floor, according to a Channel Seven report on Saturday night.

"I will urge the Prime Minister Malcolm Turnbull to change laws to protect high profile politicians and businessmen from such allegations which can turn their career upside down in a split second."

In a response to questions over the incident on Saturday, Mr Mehajer accused Fairfax Media of "silly journalism".

"In respect to the allegations I urge extreme caution in respect to any story that my [sic] be incorrect, misconceived, misconstrued or may make defamatory allegations," he said. "I reserve my rights."

It is not clear whether Mr Mehajer knew of Mr Herat senior's connection to the Lindt cafe seige.

Joel Herat escaped from the Lindt cafe siege in December 2014 after busting down the door to the cafe with fellow hostage Jarrod Hoffman and five others before two other hostages, Katrina Dawson and Tori Johnson, were killed.

The controversial Auburn deputy mayor faces separate allegations that he failed to disclose his pecuniary interests when voting on council rezoning plans at a tribunal hearing in November, in his second run-in with the state government.

The NSW Civil and Administrative Tribunal heard on Wednesday that Cr Mehajer may call character witnesses as part of his battle with the NSW Office of Local Government.